1. Field of the Invention
This invention relates to concrete screeds, and more particularly, open frame vibratory screeds.
2. Description of the Prior Art
A wide variety of vibrating concrete screeds are disclosed in the prior art. An open frame, vibrating screed is manufactured by the H. Compton Company of Conroe, Tex., and includes a plurality of pneumatic vibrators mounted at intervals on front and rear screed blades. This screed is fabricated in variable length sections, is translatable over a freshly poured concrete surface by a pair of winches and can be adjusted to provide a variable contour for the surface of the concrete being screeded. Another related concrete screed is manufactured by AWS Manufacturing, Inc. of Naperville, Ill. The AWS concrete screed also includes a wall mounting bracket attachment which is bolted to an end bracket of the screed and includes a single length of angle iron which engages the top and side surfaces of a 2.times.4 wall mounted guide rail. U.S. Pat. No. 4,030,873 (Morrison) rdiscloses a multi-element concrete screed having variable length elements and a rotating shaft which extends along the length of the screed for imparting uniform vibrations to the front and rear screed blades. All of the above described concrete screeds are vertically supported above opposing, parallel oriented side forms.
U.S. Pat. No. 3,110,234 (Oster) discloses a concrete screed having vertically adjustable blades which are translatable along parallel oriented rails. U.S. Pat. No. 3,435,740 (McGall) discloses a concrete screed including a hand operated winch for laterally translating the screed and a turnbuckle system for adjusting the concrete surface contour formed by the various sections of the screed.
U.S. Pat. No. 2,542,979 (Barnes) discloses a concrete screed having an inverted T-shaped screed blade and electric motor for imparting a vibratory motion to the screed blade.
U.S. Pat. No. 3,883,259 (Berg) discloses another concrete screed having parallel oriented blades and means for imparting vibratory motion to the blades.
The following U.S. patents disclosed other concrete screed configurations: U.S. Pat. Nos. 2,372,163 (Whiteman); 1,386,348 (Maxon); 2,866,394 (Smith); 3,008,388 (Nave); 4,073,593 (Storm); 3,095,789 (Melvin); 3,523,494 (Kraemer); 2,219,247 (Jackson); 3,113,494 (Barnes); 2,693,136 (Barnes) and 4,105,355 (King).